As semiconductor devices are miniaturized in size, the demand for reducing a parasitic capacitance between a gate and a source of a transistor is increasing. For this reason, a film (e.g., low-k film) having a relatively lower dielectric constant is considered in manufacturing semiconductor devices, instead of a silicon nitride film (SixNy film, hereinafter simply referred to as “SiN film”), which is conventionally used as a sidewall film or the like. In a silicon oxide carbon nitride film (SiOCN film) in which oxygen (O) and carbon (C) are added into the SiN film, a low dielectric constant is realized by adding O, and a wet etching resistance or a dry etching resistance which is deteriorated by adding O can be recovered or improved by adding C.
It is known that the SiOCN film is formed, for example, by performing a cycle a predetermined number of times, the cycle including: a process of supplying a silicon-containing gas to a heated wafer in a processing chamber; a process of supplying a carbon-containing gas; a process of supplying a nitriding gas; and a process of supplying an oxidizing gas, which are sequentially performed. Recently, a high dielectric constant insulating film (high-k film) is used as a gate insulating film of transistors, and thus lowering a film-forming temperature of a thin film formed near a gate, such as a sidewall film, is increasingly required. The low temperature range may be, for example, equal to or less than 600 degrees C., for example, equal to or less than 450 degrees C. However, when the film-forming temperature is lowered to the low temperature range, a deposition rate of a thin film is reduced, causing a low productivity of semiconductor devices.